Method of exploratory drilling



Dec. 2

J 5. MITCHELL G a ILLIN HOD OF EXPLQRATORY DR MET Fiied June an 45511522945F512. v

Patented Dec. 22, 1925.

UNITED STATES JOSEPH S. MITCHELL, OF CHICAGO, ILLINOIS, ASSIGNOR TO SULLIVAN monnmmr COMPANY, A CORPORATION .OF IMIASSAGH'U'SE'ITS.

manic]; or 'EXPLORATORY DRILLING.

Application filed June 4,

To all whom it may concern:

Be it known that I, JOSEPH S. MITCHELL, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Methods of Exploratory Drilling, of which the following is a full, clear, and exact specification.

My invention relates to methods of exploratory drilling.

An object of my invention is to provide an improved method of exploratory drilling. 'Anotherobject of my invention is to provide an improved means for determining the dip 5 or inclination of the bedding strata of the material encountered in core drilling. Still another object of my invention is to provide an improved method for determining the dip or inclination of bedding strata. A still further object of my invention is to provide improved means for determining both the angle and direction of the hole and the angle and direction ,,of,inclination of the bedding strata. These and other objects. and advantages of my improvement will however, hereinafter more fully appear.

In the accompanying drawings I have shown for purposes of illustration one form which the apparatus used in the practice of my invention may assume in practice.

In these drawings, Fig. 1 is a section through a core drill hole showing the bedding strata, the core drilling mechanism being removed.

Fig. '2 is a section similar to-that show .in Flg. 1, my improved surveying instru ment being disposed in place.

Fig. 3 is a sectional view similar to Fig. 1 with the core drilling mechanism also dislposed within the hole. Fig. 4 is ,a central longitudinal sectional view, partially in elevation, of my improved surveying instrument.

In this illustrative form of my invention, I have shown a recording or surveying instrument, which may obviously assume many difl'erent forms, but. herein generally designated 1," comprising a metallic casing 2, hereinv com osed .of brass tubing or other 50 non-magnetic material provided with a bore 3 suitably closed at its lower end by a removable brass plugmember 4', and at its upper end by a cap member 5, likewise composed of brass, having a threaded engagement 1924. Serial No. 717,909.

with the casing 2. In the bore 3 a glass container or tube 6, which might be-in the form of a thermos bottle or the like when excessive heat is to be encountered, is disposed suitably held in position by any suitable means, herein by cement, plaster of Paris,

member 9 ofnon-magnetic material inserted axially in the closure member 8. When it is desired to determine the angle 'of'the hole from the vertical and both the angle and the liquid I direction of the inclination of the natural bedding strata of the material being drilled, the core drilling mechanism, which comprises a drill bit 10, a resilient core lifter 11, each having a circular passage therethrough,

and a hollow core barrel 12 of the usual type, is raised from the drilled hole,"which is indicated-at 13. A tool -for rat-tailing, preferably a small diamond bit, is usedto drill a small hole 14 in the center of the hole 13 and the recording-or surveying instrument 1 is then lowered in any sultablemanner into the hole 14 and suitably rigidly held thereinas by cement as indicated at 15, or by suitable friction springs if desired. It will herein be noted that the gelatineor cement within the glasscontainer 6, being in liquid form at this time, ermits thejcompass needle to take a position between the north and south magnetic poles and in a horizontal plane. When the liquid gelae tine or liquid cement hardens, assuming a solid form and preventing any movement of the compass needle relative to "the casing" 2, the core drilling mechanism is then again lowered into the hole and the bedding strata adjacent the hole l4= in which the surveying instrument 1 is disposed, is cut free by the drillbit 10 forming a-core as indicated at 16 in which the recerding instrument is held in fixed relatiom The drillingmechanism is then again raised upwardly causing tine.

the resilient core lifter 11 to rigidly grip the core, breaking it off, and permitting the core 16 andthe recording or surveying instument 1 to be simultaneously raised with the drilling mechanism from the hole. The

core and the instrument are then removed from the core barrel and the cap 5 is unthreaded from the casing 2. The angle and. direction of inclination of the natural bedding strata may be determined by placing the top surface of the gelatine in the container in a' horizontal plane with the compass needle disposed between the north and south magnetic poles. The angle and d1- rection of the beddingstrata may then be determined by checking the strata with the compass needle and the surface of the gela- The angle and direction of the vhole may also be determined when the instrument is in this position, by checking the position of the compass needle and the top surface of the gelatine with a vertical line. Other methods of ascertaining the angle and direction of the bedding strata and the angle and direction of the hole will be clearly apparent to those skilled in the art. In

case cement or plaster of Paris was used, this is carefully worked away until the position of the compass needle is reached.

As a result of my improved recording or surveyin instrument and method, it is possible to ete'rinine not only the angle and direction of the drill .hole, as the surface of the hardened material will show the angle of the drill hole from the vertical and the position ofthe compass needle will permit the determining of the direction, but also one can ascertain the inclination from the horizontal and the direction of curvature of the natural beddng strata, which has heretofore been impossible as the core, when being removed from the hole from a great depth, often. turns several times with the core barrel due to. the torsion of thedrill rods. It will also be noted that I have provided a recording or surveying instrument of an extremely simple and compact form which may be utilized in core drill holes of various sizes, which is very simple in structure and which may be manufactured at a minimum of expense and used in connection with core drills of standard form.

While I have in this specification specifically described one form of device with which my invention may be practiced, it will be understood that this form is for purposes of illustration and that my invention may be carried out with various other forms with out departing from its spirit or the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent is:

1. The method of determining the inclination of the strata being drilled which con sists in inserting a recording instrument in the strata, securing the instrument in position in the strata, and withdrawing the instrument in fixed relation with a. section of the strata.

2. The method of determining the inclination of the strata being drilled which consists in inserting a recording instrument in the strata, securing the instrument in position in the strata, cutting out a core of the strata containing the instrument, and withdrawing the instrument in fixed relation with said core. I

3. The method of determining the inclination of the strata bein drilled which consists in boring a hole, inserting a recording instrument in a reduced portion of the hole, and withdrawing the same in fixed relation with a core of the strata.

4. The method of determinin the inclination of the strata being drille which con: sists in boring a hole, inserting a recording, instrument in a reduced portion of the hole, resuming boring of the hole to produce a core, and withdrawing the instrument in fixed relation with said core.

5 The method of determining the inclination of the strata being drilled which consists in inserting a'recording instrument in the strata, cementing the instrument in position in the strata, cutting the core of the strata encircling the same, and simultaneously withdrawing a core and the instrument in fixed relation.

6. A method of determining the inclination of bedding strata which consists in drilling a hole in the strata, drilling a second hole in the bottom of the first hole, inserting a recording instrument in the second hole, securing the instrument in position in the latter hole, separating a sectlon of the a hole in the strata, drilling a smaller hole, cementingthe instrument in position in the latter hole, resuming borin of the first hole to produce a core, and withdrawing the instrument from the hole in fixed relation with said core. I In testimony whereof I afiix m si nature.

' JOSEPH S. MI C LL. 

